1. Field of the Invention
The present invention relates to a fastener for fixing an interior or an exterior part or the like of an automobile to a predetermined vehicle body panel.
2. Description of the Related Art
Although not specifically illustrated, a fastener of this kind of a background art includes two parts of a pin made of a synthetic resin and a grommet made of a synthetic resin. The former member of the pin is provided with a head portion in a shape of a circular disk and a shaft portion in a shape of a circular cylinder hung from a lower face of the head portion. The shaft portion is formed with a large diameter groove and a small diameter groove at a side face thereof along an axial direction. The latter member of the grommet is provided with a flange portion in a shape of a circular disk and a barrel portion in a shape of a circular cylinder hung from a lower face of the flange portion. The flange portion is formed with an opening for inserting the shaft portion of the pin at a center thereof. The barrel portion is constituted such that a peripheral wall thereof is divided into a plurality of divided leg pieces via slits. Furthermore, inner faces of front end portions of the respective divided leg pieces are formed with bulged projections for individually engaging with the large diameter groove and the small diameter groove of the above-described shaft portion (refer to, for example, Japanese Patent No. 3332138).
Further, when a trim board constituting an interior part of an automobile is actually fixed to a vehicle body panel the shaft portion of the pin is inserted into the barrel portion of the grommet from a front end side thereof to provide a tacked state in which the bulged projection formed at the inner faces of the front end portions of the respective divided leg pieces of the grommet are engaged with the small diameter groove formed at the shaft portion of the pin. When the barrel portion of the grommet is inserted into respective attaching holes of the trim board and the vehicle body panel coinciding with each other under the state and the head portion of the pin is pushed to be completely brought into contact with the flange portion of the grommet the bulged projections of the respective divided leg pieces are engaged with the large diameter groove of the shaft portion, and the divided leg pieces of the grommet are expanded to open outward. Thereby, the trim board is fixed to a side of the vehicle body panel.
Therefore, although under the fastener of the background art, there is achieved an advantage of fixing the trim board and the vehicle body panel simply, on the other hand, in the state of fixing the trim board, in view of a relationship that the trim board and the vehicle body panel are pinched from inner and outer sides by the flange portion and the divided leg pieces of the grommet made of the synthetic resin, as a matter of course, a force of pinching the vehicle body panel to a hole edge of the attaching hole is weakened. Therefore, a strong pinching force cannot be exerted.